1. Field of the Invention
The present invention relates to a solid-state imaging device, a method of manufacturing the same, and an electronic apparatus, such as a camera with the solid-state imaging device.
2. Description of the Related Art
An amplification type solid-state imaging device is known which is exemplified by a MOS type image sensor, such as a CMOS (Complementary Metal Oxide Semiconductor) or the like as a solid-state imaging device. A charge transfer type solid-state imaging device is also known which is exemplified by a CCD (Charge Coupled Device) image sensor. The solid-state imaging devices are widely used for digital still cameras, digital video cameras, and the like. In recent years, as a solid-state imaging device mounted on a mobile apparatus, such as a camera-equipped mobile phone or a PDA (Personal Digital Assistant), a MOS type image sensor having a low power supply voltage is increasingly used from the viewpoint of power consumption.
A MOS solid-state imaging device includes unit pixels each having a photodiode serving as a photoelectric converter and a plurality of pixel transistors. The MOS solid-state imaging device has a pixel section (imaging area) where a plurality of unit pixels are arranged in a two-dimensional array, and a peripheral circuit area. In this solid-state imaging device, a multilayer wiring layer is provided which has multiple layers of wiring through interlayer insulating films. A plurality of pixel transistors are MOS transistors, and have three transistors of a transfer transistor, a reset transistor, and an amplification transistor, or four transistors also including a selection transistor. An on-chip color filter and overlying on-chip microlenses are formed on a light incidence side.
A CCD solid-state imaging device has a plurality of unit pixels arranged in a two-dimensional array, that is, a pixel section (imaging area) where photodiodes serving as photoelectric converters are provided and a vertical transfer register having a CCD structure is arranged to correspond to each photodiode column. The CCD type solid-state imaging device further has a horizontal transfer register having a CCD structure which transfers signal charges from the pixel section in a horizontal direction, an output section, and a peripheral circuit constituting a signal processing circuit. In this solid-state imaging device, an on-chip color filter and overlying on-chip microlenses are formed on a light incidence side.
In such a solid-state imaging device, with the reduction in size of pixels, it is necessary to improve sensitivity of pixels and to suppress color mixture. JP-A-2007-88306 discloses a MOS solid-state imaging device in which an in-layer lens is formed to be self-aligned with a base, thereby improving focusing characteristics.